The present invention relates to a high-precision transfer stage apparatus for use with lithography apparatuses, instrument apparatuses or other apparatuses and a method for producing circuit patterns utilizing the same and, more particularly, to a stage apparatus for use with an exposure apparatus to be used in a lithography process for producing particularly semiconductor devices and liquid crystal display devices and a method for forming device patterns on a photosensitive substrate plate using such an exposure apparatus.
Hitherto, a variety of exposure apparatuses have been employed in situ in a lithography process for producing semiconductor devices. Among such exposure apparatuses which currently have been employed in situ on a large-scale line, a compression projection exposure apparatus (usually called a stepper) of a step-and-repeat system is employed predominantly. In addition, there are known a projection exposure apparatus (a scanning exposure device) in a step-and-scan system so arranged as to scan a mask with a circuit pattern drawn as an original picture thereon and a photosensitive substrate plate (a semiconductor wafer) for producing devices relative to an optical projection system, a X-rays stepper so arranged as to set a mask and a photosensitive substrate plate at a given gap interval and to expose the mask and the photosensitive substrate plate to X-rays such as SOR rays in a step-and-repeat system, a electron beams exposure apparatus for drawing a circuit pattern with charged particle beams or transcribing a mask by radiation of electron beams, etc.
Many of such exposure apparatuses are provided each with a transfer stage apparatus which is so arranged as to hold a photosensitive or sensitive substrate plate (e.g., a semiconductor wafer with a photoresist layer coated thereon) and to move in a two-dimensional direction with respect to a pattern projection system (e.g., a projection system of a pattern image or the mask itself, etc.). There are known transfer stage apparatuses of various types, too. Among them, there is known a stage apparatus of a type in which a movable main stage member is held on a guide plane of a base table with a needle bearing or an air bearing and it is transferred by a drive source of a contact type using a feed screw and a nut, etc., or of a non-contact type using a combination of plural linear motors, etc.
In either case, the such stage apparatuses are connected each to plural flexible tubes for supplying vacuum pressure or pressure-applying fluid to a holder of a vacuum adsorption system for holding and adsorbing a substrate plate or an aerodynamic operation source (e.g., piston, vacuum pad part, etc.). Therefore, the movable main stage member is transferred while dragging those flexible tubes from the base table. Likewise, the movable main stage member is provided with various electrical drive sources (e.g., rotary motor, voice coil motor, piezo element, electromagnet, etc.). To those electrical drive sources are connected plural electrical wiring for supplying electrical energy from the base table side or an apparatus column side. Thus, the movable main stage member is transferred while dragging such wiring.
Further, in conventional stage apparatuses of a type in which an air guide stage of a non-contact guide structure is combined with linear motors of a non-contact type, the plural linear motors are subjected to servo control so as for a measured value of a predetermined position of the coordinates of the movable main stage member measured by a laser interferometer to be present within a predetermined error scope (e.g. xc2x10.04 xcexcm) with respect to the instructed target position. Thus, stability during the movable main stage member being transferred and stayed depends mainly upon a drive feature (torque deviation, etc.) or a servo feature because they have no sliding part on the guide surface and a mechanical contact part in the drive sources.
Moreover, in instances where the movable main stage member is transferred at an equal speed with a precision as high as, e.g. xc2x10.01%, with respect to the target speed or where it is stopped at the target position with a precision as high as, e.g. xc2x10.04 xcexcm, the main stage member is subjected to servo control, including a variation in a force (tension) caused by pulling the flexible tubes or electrical wires, a vibration of the tubes or the wiring themselves, etc., as a consequence worsening performance in transferring at a equal speed and in stopping in a predetermined position with a high degree of precision from a desired specification.
In particular, when the movable main stage member is made lightweight by using a honeycomb (hollow) structure of a ceramics material in order to raise responsiveness to frequency of the movable main stage member, various vibrations including a vibration of a power source in an air-conditioning chamber and an air vibration (sound wave) by blowing air from the air-conditioning chamber may be likely to be transmitted through the flexible tubes and the electrical wiring, thereby adversely affecting the dynamic and static features of the main stage member. As a result, they may cause deteriorating in precision of the position for transcribing circuit patterns to be formed on the substrate plate, in a resolving power thereof, and in precision of superimposition thereof.
A servo feature unlikely to undergo an influence of tension of the tubes and the wiring as well as various vibrations can be achieved by making an output capacity of various drive actuators (motors, electromagnets, etc.) for driving the movable main stage member in the directions X, Y (and Z, xcex8) remarkably strong and making a loop gain great at the time of the servo control. However, such an arrangement of the servo control may cause different problems that the stronger output capacity of the drive source may increase an exothermic amount, thereby causing a fluctuation of temperature in the air within a light path of the laser interferometer and a variation in reflectance, leading to deterioration in a precision of length measurement.
The primary object of the present invention is to provide a stage apparatus so adapted as to prevent deterioration in dynamic and static features due to an influence of various tubes and wiring connected to a movable main stage member of the stage apparatus.
The present invention has a second object to provide stage apparatus with a tube excluded therefrom, which therwise is connected to a movable stage with a function of adsorbing a substrate plate via vacuum pressure in an exchangeable manner by supplying a pressure-reducing fluid (vacuum pressure) thereto.
Further, the present invention has a third object to provide a lithography exposure apparatus with the such stage apparatus loaded thereon for exposing a circuit device for a semiconductor element or a liquid crystal display element and a method for producing a circuit pattern (a device pattern) by utilizing an improved operation method of the such exposure apparatus.
The present invention is applied to a transfer stage apparatus having a base structure body (e.g. a base table, etc.), a stage structure body (e.g. a movable main stage member, etc.) disposed so as to be movable in and along a predetermined plane (XY-plane) defined by the base structure body, and a substrate plate-loading part (e.g. a holder, etc) for holding a processing substrate plate (e.g. a wafer, etc.) on the stage structure body.
Further, the movable stage apparatus according to the present invention is provided with an electrical drive unit (e.g. a group of an electromagnetic drive unit and a permanent magnet, etc.) for transferring the stage structure body in a non-contact system along a predetermined flat plane (a defined flat plane) of the base structure body in a state floating from the base structure body; an electrical adsorption unit (e.g. an electrode for electrostatic adsorption, etc.) for adsorbing the processing substrate plate on the substrate plate-loading part; a re-chargeable battery (e.g. nickel-cadmium battery, etc.) for accumulating electrical energy disposed in the stage structure body; a feed control circuit (e.g. CPU, high voltage control circuit, drive circuit, etc.) for controlling electrical energy from the battery and supplying the electrical energy to at least one of the electrical drive unit and the electrical adsorption unit disposed in the stage structure body; and a receiving circuit (e.g. RFC, a digital converter circuit or a feed terminal part and a data coupler part, etc.) for receiving control information for giving an instruction of an action of the feed control circuit disposed in the stage structure body.
Furthermore, the present invention is applied to the transfer stage apparatus having a base structure body (e.g. a base table, etc.), a stage structure body (e.g. a movable main stage member, etc.) disposed so as to be movable in or along a predetermined plane (XY-plane) defined by the base structure body, and a substrate plate-loading part (e.g. a holder, etc) for holding a processing substrate plate (e.g. a wafer, etc.) on the stage structure body, in which the transfer stage apparatus is further provided with an electrostatic adsorption unit (e.g. an electrode, etc.) for electrostatically adsorbing the processing substrate plate on the substrate plate-loading part; a re-chargeable battery (e.g. nickel-cadmium battery, etc.) disposed in the stage structure body; a feed control circuit (e.g. CPU, high voltage control circuit, etc.) for controlling electrical energy from the battery and supplying the electrical energy to the electrostatic adsorption unit disposed in the stage structure body; and a receiving circuit (e.g. FRC, a digital converter circuit or a feed terminal part and a data coupler part, etc.) for receiving control information for giving an instruction of an action of the feed control circuit disposed in the stage structure body.
Moreover, the present invention is applied to a method for producing a circuit device on a processing substrate plate by the step of transferring a movable stage structure body (e.g. a movable main stage member, etc.) on a base structure body (e.g. a base table, etc.) in accordance with a control program stored in advance (e.g. stored in a minicomputer or a control unit board, etc.) and the step of transcribing a circuit pattern on each of plural sheets of processing substrate plates (e.g. wafers, etc.) loaded on the stage structure body so as to be exchangeable.
In the present invention, the stage structure body is provided with a rechargeable battery (e.g. nickel-cadmium battery, etc.) for supplying electrical energy to at least one of a first actuator (e.g. a holder and an electrode on the surface thereof, etc.) for adsorbing and fixing the processing substrate plate on the stage structure body and a second actuator (e.g. a motor for minute motion, etc.) for minutely transferring the processing substrate plate on the stage structure body with three freedoms or more and with an electrical receipt edge orifice (e.g. a receipt terminal part, etc.) for charging the battery, the base structure body is provided with a feed edge orifice (e.g. a feed terminal part, etc.) for sending a charging electric current to the battery upon connection to the receipt edge orifice when the stage structure body is located in a predetermined standby position (e.g. a loading position, etc.); and a command or parameter for transferring the stage structure body to the standby position for charging the battery is made registrable as a portion of a control program at an appropriate point of time during a period of time during which the plural sheets of processing substrate plates are being processed.
The present invention is applied to the transfer stage apparatus having a base structure body (e.g. a base table, a column, etc.) and a stage structure body (e.g. a main stage member, etc.) moving along a predetermined plane (XY-plane) defined by the base structure body and forming at a portion thereof with a loading surface (e.g. a holder, etc.) for adsorbing a processing substrate plate (e.g. a wafer, etc.) under reduced pressure, in which the stage apparatus further comprises a feed edge orifice disposed at a portion of the base structure body for sending a negative pressure fluid for adsorbing the processing substrate plate on the loading surface of the stage structure body; a receipt edge orifice for receiving the negative pressure fluid on the stage structure body side, which is disposed at a portion of the stage structure body so as to be engageable with the feed edge orifice when the stage structure body is transferred to a predetermined waiting position (e.g. a loading position, etc.); a valve mechanism for opening or closing a path of the negative pressure fluid, extending between the feed edge orifice and the loading surface of the stage structure body; and a control unit for bringing the valve mechanism into an open state during engagement of the feed edge orifice with the receipt edge orifice when the stage structure body is transferred to the waiting position and for bringing the valve mechanism into a closed state during non-engagement of the feed edge orifice with the receipt edge orifice.
The present invention can be further applied to a transfer stage apparatus having a base structure body and a stage structure body moving along a predetermined plane (XY-plane) defined by the base structure body and forming at its portion with a loading surface (e.g. a holder, etc.) adsorbing a processing substrate plate under reduced pressure, in which the stage apparatus further comprises a sending mechanism disposed at a portion of the base structure body for sending a negative pressure fluid to the loading surface of the stage structure body for adsorbing a processing substrate plate; and a receiving mechanism, disposed at a portion of the stage structure body so as to be engaged with the feed mechanism when the stage structure body is located in a predetermined waiting position (e.g. a loading position, etc.), for leading the negative pressure fluid from the feed mechanism to the loading surface of the stage structure body during engagement with the feed mechanism and for blocking communication with open air during non-engagement with the feed mechanism.
Moreover, the present invention can be applied to a method for forming an image of a circuit pattern on an exposing substrate plate using a projection exposure apparatus having a first stage structure body movable at least one-dimensionally upon scanning exposure while adsorbing and holding a mask substrate plate with the circuit pattern formed thereon and a second stage structure body movable at least one-dimensionally upon scanning exposure while adsorbing and holding the exposing substrate plate.
And, the present invention is practiced by executing the step of loading a first accumulation member (e.g. battery, a tank chamber, etc.) on the first stage structure body (e.g. a reticle stage, etc.), the first accumulation member being for accumulating energy (e.g. electricity for electrostatic adsorption or a pressure-reducing fluid for vacuum adsorption, etc.) necessary for sustaining the adsorption of a mask substrate plate (e.g. a reticle, etc.) over a predetermined period of time on the first stage structure body, and sustaining a self-sustaining adsorption of the mask substrate plate by energy from the first accumulation member (e.g. battery, tank chamber, etc.) during a period of time during which the first stage structure body is apart from a waiting position, while a new energy (e.g. electricity, pressure-reducing fluid, etc.) can be supplemented to the first accumulation member when the first stage structure body is located in the waiting position for exchanging the mask substrate plate; and the step of loading a second accumulation member (e.g. battery, tank chamber, etc.) on the second stage structure body (e.g. a movable main stage member, etc.), the second accumulation member being for accumulating energy (e.g. electricity for electrostatic adsorption, pressure-reducing fluid for vacuum adsorption, etc.) necessary for continually adsorbing the exposing substrate plate on the second stage structure body over a predetermined period of time, and sustaining a self-sustaining adsorption of the exposing substrate plate by energy from the second accumulation member (e.g. battery, tank chamber, etc.) during a period of time during which the second stage structure body is apart from the waiting position (a position for exchanging wafers), while a new energy can be supplemented to the second accumulation member (e.g. battery, tank chamber, etc.) when the second stage structure body is located in the waiting position for exchanging the exposing substrate plate.
The present invention can further be applied to a method for producing a circuit device on a processing substrate plate using a lithography apparatus in which the processing substrate plate is held on a stage structure body (e.g. a movable main stage member, etc.) transferring on a base structure body and a desired circuit pattern is exposed to the processing substrate plate by transferring the stage structure body.
The present invention is practiced by the step of carrying the processing substrate plate toward a predetermined loading position (e.g. the wafer exchanging position, etc.) defined on the base structure body and transferring the stage structure body to the loading position; the step of delivering the processing substrate plate onto a substrate plate-loading part (e.g. a holder, etc.) of the stage structure body in the loading position; the step of supplying a pressure-reducing fluid or a pressure-applying fluid to a closed space part (e.g. a groove of the holder, an adsorption pad of the upper stage member, an adsorption. aperture of the lift pin, an air jack, etc.) formed in the stage structure body through a receipt edge orifice disposed in the stage structure body during a period of time during which the stage structure body is located in the loading position; and the step of blocking communication of the receipt edge orifice with the atmosphere during a period of time during which the stage structure body is located apart from the loading position.
The present invention is based on the basic concept that the number of the tubes and wiring is decreased to the least possible number in order to decrease an influence caused by the tension of the tubes and the wiring to be connected otherwise to the movable main stage member. In one of the best modes of the present invention, the stage apparatus is configured in such a manner that a vacuum operation source (e.g. a wafer or a holder with a mask adsorbed thereon, etc.) disposed in the movable main stage member or an aerodynamic operation source (e.g. an air bearing for floating, etc.) is replaced with an electrical operation source by an electromagnetic force or an electrostatic force and the electrical energy for operating the electrical operation source as well as the electrical operation source (e.g. a coil of a linear motor, etc.) for transferring the movable main stage member is supplied through a drive circuit from a battery loaded on the movable main stage member and further that the drive circuit is controlled in a wireless system by electric radio or optical communications.
In another preferred mode of the present invention, at least a flexible tube for supplying vacuum pressure or compressed air is not needed by replacing the vacuum operation source or the aerodynamic operation source in the movable main stage member is replaced with the electrical operation source. At the same time, a bundle of large wire lines for supplying electric power is not needed by loading the battery and the drive circuit on the movable main stage member. In this mode, therefore, only a fine cable for communications is connected to the drive circuit, thereby making the tension of the cables added to the movable main stage member smaller.
Further, in the stage apparatus in another mode of the present invention, only a flexible tube for supplying vacuum pressure or compressed air is not used and the electrical energy is supplied by a wire line as usual. In this case, the battery loaded on the movable main stage member is used for feeding electrical energy to an adsorption operation source by electrostatic energy or a small-size motor having a low consumption of electric power, while an electromagnetic actuator having a large electric power (e.g. linear motor, coil for electromagnetic floating, etc.) for transferring the movable main stage member on the base table is connected in a conventional wiring system.
In instances where the battery is loaded on the movable main stage member, the battery may be an electrolytic condenser having a large capacity, in addition to a battery of a re-chargeable type, such as a nickel-cadmium battery, a nickel-hydrogen battery, etc. In either case, however, it requires the charging work at an appropriate timing. When the stage apparatus according to the present invention is applied to the exposure apparatus, accordingly, the stage apparatus is structured in such a manner that the movable main stage member is aligned with the standby position at an appropriate timing during a period of time during which the substrate plates are loaded one by one on the stage apparatus and subjected to exposure processing and that the command (e.g. transferring and staying the stage, specifying the charging mode, etc.) and the parameter (e.g. the position of staying the stage, charging time, etc.) for charging the battery, which connects the feed terminal for charging on the base table side or the apparatus column side to the receiving terminal for charging on the movable main stage member side in that position, need be formed into configuration (e.g. software, etc.) as being capable of being registered in a program for controlling the exposure apparatus.
The standby position referred to herein may be a position in which the movable main stage member can be stayed over a relatively long period of time, e.g. preferably a loading or unloading position upon exchanging wafers and loading the wafer on the stage apparatus or a reset position (the physically original position of the stage, etc.) for resetting a laser interferometer for measuring the position of the movable main stage member, etc.
Further, in another mode of the present invention, in order to do without the tube for use with negative pressure fluid for vacuum adsorption extending from the holder for vacuum adsorbing the substrate plate, such as the wafer or reticle, etc., to the stage base table or the apparatus column, the stage apparatus is structured such that the feed edge orifice (an outlet) for supplying the negative pressure fluid (vacuum pressure) is fixed on the base table side or the apparatus column side and the receipt edge orifice or the receiving mechanism (an inlet) connectable to the outlet is disposed on the holder or on the movable main stage member with the holder loaded thereon in such a manner that the adsorption of the wafer on the holder is started by connection of the outlet to the inlet upon stopping the movement of the movable main stage member in the predetermined standby position (e.g. the position for exchanging the wafers, etc.). Further, when the movable main stage member is transferred from the standby position, a passive or active valve mechanism is operated so as to block the communication of the adsorbing pressure-reduced path with the atmosphere via the inlet, thereby sustaining the action for adsorbing the wafer on the holder.
When the wafer is to be adsorbed by the aid of vacuum pressure on the movable main stage member in the manner as described hereinabove, the holder or the movable main stage member may be provided with a preliminary pressure-reducing chamber (e.g. a reserve tank, a tank chamber, etc.) that can be communicated with the adsorption surface of the holder, thereby supplementing an extreme reduction in the time for sustaining the adsorption by the aid of an extremely small total volume of the pressure-reducing part (e.g. adsorption grooves or fine concave portions having a depth of approximately 1 millimeter) alone formed on the adsorption surface of the holder and as a result maintaining a sufficient high vacuum adsorption force over a long period of time.
Moreover, the movable stage apparatus according to the present invention can be likewise applied to a mask stage apparatus for transferring a mask or a reticle with a circuit pattern drawn thereon in a one-dimensional or two-dimensional direction with a large stroke. In particular, it is effective to apply the movable stage apparatus according to the present invention to a mask stage apparatus which is structured in such a manner that the mask or the reticle is subjected to scanning exposure with a stroke having the size greater than the size of the mask or the reticle, in order to expose the plural shot areas on a photosensitive substrate plate one by one in a step-and-scan system. In this case, too, the present invention can likewise provide the advantages that the mask stage apparatus can do without flexible tubes and electrical wiring for vacuum adsorption which are otherwise pulled by the movable main stage member or can reduce the number of them to smaller numbers than conventional ones, in order to hold the mask or the reticle by vacuum adsorption, electrostatic adsorption or any other appropriate means.
In addition, the present invention can likewise build a system for an aerodynamic drive system for transferring a movable member by the pressure-applying fluid as well as a vacuum adsorption mechanism necessary in the movable main stage member. In this case, the movable main stage member can achieve the advantage that it can avoid pulling and dragging the flexible tubes etc. for supplying the pressure-applying fluid necessary for the aerodynamic drive system. This advantage can be attained primarily by mounting the valve mechanism for opening or closing a supply path for supplying the pressure-applying fluid connected to the aerodynamic drive source in the movable main stage member.
Furthermore, the present invention is structured in such a manner that, while the substrate plate is adsorbed via vacuum pressure on the holder by the self-sustaining adsorption system constructed by the valve mechanism or the preliminary pressure-reducing chamber on the movable main stage member, a monitor program is operated to monitor the adsorption force to determine if the adsorption force is acting upon the substrate plate in a normal way. This allows an automatic management, etc. of checking an occurrence of a leakage between the substrate plate and the holder, a variation in the adsorption force due to such a leakage, a time for sustaining the adsorption, etc., thereby predicting in advance the possibility that the substrate plate deviates from its predetermined position on the holder by acceleration or deceleration of the movable main stage member. Accordingly, the lithography process using the exposure apparatus can be operated with high security and a turnover can be improved in producing devices such as semiconductor elements, liquid crystal display elements, etc.